The adequate anti coagulation is an absolute necessity in order to avoid the extra-corporal circuit and haemodialyzer clotting and to perform an adequate renal replacement therapy during a haemodialysis session. In the cases of multiple coagulation defects having high haemorrhagic risk factors and the patients under anti-coagulation therapy, it is recommended to reduce the heparin doses or to do heparin free haemodialysis. Several strategies of low heparin or heparin free haemodialysis have been proposed till now, without a real success. The heparin coated polyacrylonitrile haemodialyser (EVODIAL) has been reported to have 90 % successful heparin-free haemodialysis sessions. On the other hand, the vitamin E coated polysulphone (VIE) has also been reported to have an anti oxidative and anti-thrombotic properties and a capacity to improve the haemorrheological factors of human blood, hence having a promising future to perform a successful haemodialysis session with less or without heparin. This randomised, multi-centric, cross-over and open study has been designed to compare non inferiority of the haemodialyzer VIE 2,1 versus EVODIAL2,2 with a risk alfa of 5% and an absolute accepted difference of 12 %.